340 lines
8.6 KiB
Plaintext
340 lines
8.6 KiB
Plaintext
---
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title: Snapshot (v0.31)
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description: API reference for qiskit.pulse.Snapshot in qiskit v0.31
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in_page_toc_min_heading_level: 1
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python_api_type: class
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python_api_name: qiskit.pulse.Snapshot
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---
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# Snapshot
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<Class id="qiskit.pulse.Snapshot" isDedicatedPage={true} github="https://github.com/qiskit/qiskit/tree/stable/0.18/qiskit/pulse/instructions/snapshot.py" signature="Snapshot(label, snapshot_type='statevector', name=None)" modifiers="class">
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Bases: `qiskit.pulse.instructions.instruction.Instruction`
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An instruction targeted for simulators, to capture a moment in the simulation.
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Create new snapshot.
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**Parameters**
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* **label** (`str`) – Snapshot label which is used to identify the snapshot in the output.
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* **snapshot\_type** (`str`) – Type of snapshot, e.g., “state” (take a snapshot of the quantum state). The types of snapshots offered are defined by the simulator used.
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* **name** (`Optional`\[`str`]) – Snapshot name which defaults to `label`. This parameter is only for display purposes and is not taken into account during comparison.
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**Raises**
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[**PulseError**](qiskit.pulse.PulseError "qiskit.pulse.PulseError") – If snapshot label is invalid.
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## Methods
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<span id="qiskit-pulse-snapshot-append" />
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### append
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<Function id="qiskit.pulse.Snapshot.append" signature="Snapshot.append(schedule, name=None)">
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Return a new [`Schedule`](qiskit.pulse.Schedule "qiskit.pulse.Schedule") with `schedule` inserted at the maximum time over all channels shared between `self` and `schedule`.
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**Parameters**
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* **schedule** (*Union\['Schedule', 'Instruction']*) – Schedule or instruction to be appended
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* **name** (`Optional`\[`str`]) – Name of the new schedule. Defaults to name of self
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**Returns**
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A new schedule with `schedule` a this instruction at t=0.
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**Return type**
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[Schedule](qiskit.pulse.Schedule "qiskit.pulse.Schedule")
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</Function>
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<span id="qiskit-pulse-snapshot-assign-parameters" />
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### assign\_parameters
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<Function id="qiskit.pulse.Snapshot.assign_parameters" signature="Snapshot.assign_parameters(value_dict)">
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Modify and return self with parameters assigned according to the input.
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**Parameters**
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**value\_dict** (`Dict`\[`ParameterExpression`, `Union`\[`ParameterExpression`, `float`]]) – A mapping from Parameters to either numeric values or another Parameter expression.
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**Return type**
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`Instruction`
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**Returns**
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Self with updated parameters.
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</Function>
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<span id="qiskit-pulse-snapshot-ch-duration" />
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### ch\_duration
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<Function id="qiskit.pulse.Snapshot.ch_duration" signature="Snapshot.ch_duration(*channels)">
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Return duration of the supplied channels in this Instruction.
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**Parameters**
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**\*channels** – Supplied channels
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**Return type**
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`int`
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</Function>
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<span id="qiskit-pulse-snapshot-ch-start-time" />
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### ch\_start\_time
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<Function id="qiskit.pulse.Snapshot.ch_start_time" signature="Snapshot.ch_start_time(*channels)">
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Return minimum start time for supplied channels.
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**Parameters**
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**\*channels** – Supplied channels
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**Return type**
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`int`
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</Function>
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<span id="qiskit-pulse-snapshot-ch-stop-time" />
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### ch\_stop\_time
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<Function id="qiskit.pulse.Snapshot.ch_stop_time" signature="Snapshot.ch_stop_time(*channels)">
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Return maximum start time for supplied channels.
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**Parameters**
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**\*channels** – Supplied channels
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**Return type**
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`int`
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</Function>
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<span id="qiskit-pulse-snapshot-draw" />
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### draw
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<Function id="qiskit.pulse.Snapshot.draw" signature="Snapshot.draw(dt=1, style=None, filename=None, interp_method=None, scale=1, plot_all=False, plot_range=None, interactive=False, table=True, label=False, framechange=True, channels=None)">
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Plot the instruction.
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**Parameters**
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* **dt** (`float`) – Time interval of samples
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* **style** (*Optional\[SchedStyle]*) – A style sheet to configure plot appearance
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* **filename** (`Optional`\[`str`]) – Name required to save pulse image
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* **interp\_method** (`Optional`\[`Callable`]) – A function for interpolation
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* **scale** (`float`) – Relative visual scaling of waveform amplitudes
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* **plot\_all** (`bool`) – Plot empty channels
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* **plot\_range** (`Optional`\[`Tuple`\[`float`]]) – A tuple of time range to plot
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* **interactive** (`bool`) – When set true show the circuit in a new window (this depends on the matplotlib backend being used supporting this)
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* **table** (`bool`) – Draw event table for supported instructions
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* **label** (`bool`) – Label individual instructions
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* **framechange** (`bool`) – Add framechange indicators
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* **channels** (`Optional`\[`List`\[`Channel`]]) – A list of channel names to plot
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**Returns**
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A matplotlib figure object of the pulse schedule
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**Return type**
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matplotlib.figure
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</Function>
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<span id="qiskit-pulse-snapshot-flatten" />
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### flatten
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<Function id="qiskit.pulse.Snapshot.flatten" signature="Snapshot.flatten()">
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Return itself as already single instruction.
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**Return type**
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`Instruction`
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</Function>
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<span id="qiskit-pulse-snapshot-insert" />
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### insert
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<Function id="qiskit.pulse.Snapshot.insert" signature="Snapshot.insert(start_time, schedule, name=None)">
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Return a new [`Schedule`](qiskit.pulse.Schedule "qiskit.pulse.Schedule") with `schedule` inserted within `self` at `start_time`.
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**Parameters**
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* **start\_time** (`int`) – Time to insert the schedule schedule
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* **schedule** (*Union\['Schedule', 'Instruction']*) – Schedule or instruction to insert
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* **name** (`Optional`\[`str`]) – Name of the new schedule. Defaults to name of self
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**Returns**
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A new schedule with `schedule` inserted with this instruction at t=0.
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**Return type**
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[Schedule](qiskit.pulse.Schedule "qiskit.pulse.Schedule")
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</Function>
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<span id="qiskit-pulse-snapshot-is-parameterized" />
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### is\_parameterized
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<Function id="qiskit.pulse.Snapshot.is_parameterized" signature="Snapshot.is_parameterized()">
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Return True iff the instruction is parameterized.
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**Return type**
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`bool`
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</Function>
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<span id="qiskit-pulse-snapshot-shift" />
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### shift
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<Function id="qiskit.pulse.Snapshot.shift" signature="Snapshot.shift(time, name=None)">
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Return a new schedule shifted forward by time.
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**Parameters**
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* **time** (`int`) – Time to shift by
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* **name** (`Optional`\[`str`]) – Name of the new schedule. Defaults to name of self
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**Returns**
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The shifted schedule.
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**Return type**
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[Schedule](qiskit.pulse.Schedule "qiskit.pulse.Schedule")
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</Function>
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## Attributes
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### channel
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<Attribute id="qiskit.pulse.Snapshot.channel">
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Return the `Channel` that this instruction is scheduled on; trivially, a `SnapshotChannel`.
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**Return type**
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`SnapshotChannel`
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</Attribute>
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### channels
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<Attribute id="qiskit.pulse.Snapshot.channels">
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Returns the channels that this schedule uses.
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**Return type**
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`Tuple`\[`SnapshotChannel`]
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</Attribute>
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### duration
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<Attribute id="qiskit.pulse.Snapshot.duration">
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Duration of this instruction.
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**Return type**
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`int`
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</Attribute>
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### id
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<Attribute id="qiskit.pulse.Snapshot.id">
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Unique identifier for this instruction.
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**Return type**
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`int`
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</Attribute>
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### instructions
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<Attribute id="qiskit.pulse.Snapshot.instructions">
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Iterable for getting instructions from Schedule tree.
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**Return type**
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`Tuple`\[`Tuple`\[`int`, `Instruction`]]
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</Attribute>
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### label
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<Attribute id="qiskit.pulse.Snapshot.label">
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Label of snapshot.
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**Return type**
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`str`
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</Attribute>
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### name
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<Attribute id="qiskit.pulse.Snapshot.name">
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Name of this instruction.
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**Return type**
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`str`
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</Attribute>
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### operands
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<Attribute id="qiskit.pulse.Snapshot.operands">
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Return instruction operands.
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**Return type**
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`Tuple`
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</Attribute>
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### parameters
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<Attribute id="qiskit.pulse.Snapshot.parameters">
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Parameters which determine the instruction behavior.
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**Return type**
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`Set`
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</Attribute>
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### start\_time
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<Attribute id="qiskit.pulse.Snapshot.start_time">
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Relative begin time of this instruction.
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**Return type**
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`int`
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</Attribute>
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### stop\_time
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<Attribute id="qiskit.pulse.Snapshot.stop_time">
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Relative end time of this instruction.
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**Return type**
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`int`
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</Attribute>
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### type
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<Attribute id="qiskit.pulse.Snapshot.type">
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Type of snapshot.
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**Return type**
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`str`
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</Attribute>
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</Class>
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